1. Field of the Invention
The present invention relates to the control of voltage-controlled switches, and especially the control of power switches.
2. Discussion of the Related Art
When a control voltage capable of making a voltage-controlled switch operate in a desired conduction state is abruptly applied to said switch, an overcurrent tends to occur in the switch at the turning-on. In particular, in the case of a power switch connected to an inductive load such as an electric motor winding capable of causing voltages on the order of several tens of volts, the overcurrent is likely to damage the switch. To avoid this problem, power switch control devices varying the voltage by stages have been provided. In the case where the power circuit is for example a motor control circuit operating on the mains, and where the power switch is an IGBT or MOS power transistor, the control circuit must provide high voltages and conduct high currents, and no control integrated device of such power switches is currently known.